1. Field of the Invention
The present invention relates to a method of varying the capacity of a hard disk drive during its manufacturing process, and in particular, to a method of varying the capacity of a hard disk drive by avoiding the use of a head/disk combination which has defects generated during a manufacturing process.
2. Description of the Related Art
A hard disk drive, which is widely used as an auxiliary memory device of a computer system, generally employs a multi-platter arrangement to maximize data recording capacity and reduce its manufacturing cost. In such a multi-platter hard disk drive, a plurality of disks are installed around a rotating actuator, that is, a driving shaft of a spindle motor, usually in four or six head/disk combinations. A head/disk combination indicates a disk surface and a head positioned over the disk surface. The performance of the head/disk combinations is checked in several tests because the hard disk drive generally requires very accurate position control and high-speed data access. Thus, a drive manufacturing company brings drives to the market whose head/disk combinations finally have passed repeated tests such as defect scanning, error rate measurement, and writing and reading of various data patterns.
However, most drive failures generated during a manufacturing process derive from one or two of four or six head/disk combinations, which turn out to have a lack of head error rate margin, disk defects, or scratches. To cope with a disk failure, the drive manufacturing company takes actions including servo write, replacement of a head stack and a disk, and so on, depending on the type of the disk failure, thus increasing manufacturing costs. Further, if a hard disk drive needs rework due to a defective head/disk combination, the hard disk drive is vulnerable to damage during handling and to contamination. As a result, the hard disk drive may fail again.
The following each disclose features in common with the present invention but do not teach or suggest the specifically recited method of varying the capacity of hard disk drive during its manufacturing process in accordance with the present invention: U.S. Pat. No. 5,740,358 to Geldman et al., entitled Defect Management And Split Field Processing In Disk Storage Systems, U.S. Pat. No. 5,654,841 to Hobson et al., entitled Detection Of Mechanical Defects In A Disc Drive Using Injected Test Signals, U.S. Pat. No. 5,657,176 to Moribe et al., entitled Method And Apparatus For Optimizing The Recording And Reproducing Of Information From Magnetic Disks, U.S. Pat. No. 5,442,638 to Awad et al., entitled Apparatus And Method For Recording Over Defects In Storage Media, U.S. Pat. No. 5,537,264 to Pinteric, entitled Method For Optimally Selecting Media Transfer Rates For Different Data Heads Based On Individual Data Head Performance, U.S. Pat. No. 5,132,956 to Ichikawa, entitled Optical Recording/Reproducing Apparatus In Which Defective Sectors Are Altered, U.S. Pat. No. 5,212,677 to Shimote et al., entitled Defect Inspecting Apparatus For Disc-Shaped Information Recording Media, U.S. Pat. No. 5,280,395 to Matsuzaki, entitled Hard Disc Track Defect Detecting Apparatus, U.S. Pat. No. 4,949,036 to Bezinque et al., entitled Disc Drive Error Mapping Using Threshold Comparison Methods, U.S. Pat. No. 5,253,256 to Oyama et al., entitled Array Disk Apparatus With Unsuccessful Reconstruction Indicating Function, U.S. Pat. No. 5,568,627 to Leshay et al., entitled Header Verification In A Disk Drive Using Sector Histories For Improved Format Efficiency, and U.S. Pat. No. 5,568,606 to Dobbek, entitled Method And Apparatus For Maximizing Effective Disk Capacity Using Adaptive Skewing.